基于城市酒店对位置做热点图

来源：互联网发布：win7家长控制软件编辑：程序博客网时间：2024/04/30 09:06

最近在开发公司得基于用户行为日志，分析某个城市那个地方打开得app多，那个地方入住酒店多，该功能可以知道城市得热门地方，和那个地方开酒店比较火

由于公司得日志，是放在mysql数据库中，而且没有单个用户是访问的城市字段，只有当前用户的经纬度和搜索的经纬度，如果通过百度的API去获得城市酒店的话，百度API不会让调用那么多次，于是想到通过经纬度去得到基于hash的值，通过该值的不同位数，来确定是否属于该城市

代码如下：

private static intnumbits = 6 * 5;

final staticchar[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8',

'9', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 'p',

'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };

final static HashMap<Character, Integer>lookup = new HashMap<Character, Integer>();

static {

int i = 0;

for (char c :digits)

lookup.put(c, i++);

}

public staticvoid main(String[] args) throws Exception{

System.out.println(new Geohash().encode(30.4066211031716,118.36380581742704));

System.out.println(new Geohash().encode(30.5814,114.279));

System.out.println(new Geohash().encode(30.47,114.42));

System.out.println(new Geohash().encode(30.61,114.15));

System.out.println(new Geohash().encode(30.4675290000,114.5259580000));

}

public double[] decode(String geohash) {

StringBuilder buffer = new StringBuilder();

for (char c : geohash.toCharArray()) {

int i = lookup.get(c) + 32;

buffer.append( Integer.toString(i, 2).substring(1) );

}

BitSet lonset = new BitSet();

BitSet latset = new BitSet();

//even bits

int j =0;

for (int i=0; i<numbits*2;i+=2) {

boolean isSet = false;

if ( i < buffer.length() )

isSet = buffer.charAt(i) == '1';

lonset.set(j++, isSet);

}

//odd bits

j=0;

for (int i=1; i<numbits*2;i+=2) {

boolean isSet = false;

if ( i < buffer.length() )

isSet = buffer.charAt(i) == '1';

latset.set(j++, isSet);

}

double lon = decode(lonset, -180, 180);

double lat = decode(latset, -90, 90);

return new double[] {lat, lon};

}

private double decode(BitSet bs,double floor, double ceiling) {

double mid = 0;

for (int i=0; i<bs.length(); i++) {

mid = (floor + ceiling) / 2;

if (bs.get(i))

floor = mid;

else

ceiling = mid;

}

return mid;

}

public String encode(double lat,double lon) {

BitSet latbits = getBits(lat, -90, 90);

BitSet lonbits = getBits(lon, -180, 180);

StringBuilder buffer = new StringBuilder();

for (int i = 0; i <numbits; i++) {

buffer.append( (lonbits.get(i))?'1':'0');

buffer.append( (latbits.get(i))?'1':'0');

}

return base32(Long.parseLong(buffer.toString(), 2));

}

private BitSet getBits(double lat,double floor, double ceiling) {

BitSet buffer = new BitSet(numbits);

for (int i = 0; i <numbits; i++) {

double mid = (floor + ceiling) / 2;

if (lat >= mid) {

buffer.set(i);

floor = mid;

} else {

ceiling = mid;

}

return buffer;

}

public static String base32(long i) {

char[] buf = new char[65];

int charPos = 64;

boolean negative = (i < 0);

if (!negative)

i = -i;

while (i <= -32) {

buf[charPos--] = digits[(int) (-(i % 32))];

i /= 32;

}

buf[charPos] = digits[(int) (-i)];

if (negative)

buf[--charPos] = '-';

return new String(buf, charPos, (65 - charPos));

}

通过基于hash得到某个城市列表下面的用户行为日志，通过该行为日志应用KM算法来确定用我们app打开查看城市酒店的热点

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